Article ID: MI-160
We compared transpirations and vase lives of cut hydrangea (Hydrangea spp.) flowers using two cultivars with lacecap inflorescence (‘Blue sky’ and ‘S-1’) and their mutants with hortensia inflorescence (‘BM-1’ and ‘SM-1’). There was no significant difference in the transpirations from cut flowers with the lacecap and hortensia inflorescences in the two cultivars. However, transpiration from ‘S-1’ cut flowers tended to exhibit higher transpiration than ‘SM-1’. There was also no significant difference in the vase lives of ‘Blue sky’ and ‘BM-1’. However, ‘S-1’ had a significantly shorter vase life (3 days) than its mutant ‘SM-1’. This was due to the greater number of total florets in ‘S-1’ cut flowers than ‘SM-1’. The non-decorative floret clusters and clusters of petals, stamens, and pistil of decorative florets exhibited lower temperatures than decorative sepals in both ‘Blue sky’ and ‘BM-1’ on thermal images. Therefore, we estimated the transpiration from the non-decorative florets and studied the effect of removal of non-decorative florets on the vase life of cut flowers using two lacecap cultivars, ‘Blue sky’ and ‘Fairy eye’. Estimated transpirations from the non-decorative florets of ‘Blue sky’ and ‘Fairy eye’ accounted for approximately 61.8% and 39.7%, respectively, of total transpirations per cut flower, and the removal of non-decorative florets significantly extended the vase lives of cut flowers (18 and 22 days, respectively). The difference in the contribution of the non-decorative florets to the transpiration between the cultivars is due to the difference in the number of non-decorative florets in the inflorescences. We conclude that the use of cut flowers that do not bear too many non-decorative florets and/or treatments that suppress the transpiration from non-decorative florets would be effective in extending the vase life of cut hydrangea flowers with lacecap inflorescence.
